Author(s): COLOSIO, A., VAN DYCK, M., BOONE, J., Institution: JEAN MONNET UNIVERSITY SAINT-ETIENNE, Country: FRANCE, Abstract-ID: 1706

INTRODUCTION:
In resistance training, one-repetition maximum (1RM) is routinely used as a modality-specific anchor to scale relative intensity. By contrast, endurance exercise lacks a simple maximal anchor for short severe efforts. Sprint peak power output (PPO) represents a plausible cycling-specific reference to express relative intensity in the severe domain.
This study aimed to explore whether expressing severe-intensity cycling relative to PPO structures time-to-exhaustion (TTE) responses and reduces inter-individual dispersion at higher relative intensities, and to contrast this behaviour with tolerance patterns observed in paced resistance exercise prescribed as %1RM.
METHODS:
Isokinetic sprint PPO and back squat 1RM were assessed in ten trained men (22.8 ± 0.8 y; 73.9 ± 7.1 kg) in a preliminary session. Then, participants performed 8 different testing sessions in a randomized order, respectively constant-load cycling trials at 25, 35, 50, and 75% PPO or paced back-squat to failure at 25, 35, 50, and 75% 1RM. Heart rate, blood lactate concentration, ratings of perceived exertion (RPE), and vastus lateralis muscle oxygen saturation (SmO2, NIRS) were recorded. Effects of intensity and modality on TTE were analysed using two-way repeated-measures ANOVA. Linear regression assessed the association between relative intensity and TTE. Inter-individual dispersion was described using the standard deviation of data.
RESULTS:
In cycling, TTE decreased non-linearly with increasing %PPO (25%: 8:51 ± 6:39 min; 35%: 1:38 ± 0:31 min; 50%: 0:29 ± 0:13 min; 75%: 0:02 ± 0:02 min; p < 0.001). Inter-individual dispersion was markedly greater at 25% PPO and substantially reduced at ≥35%. The association between %PPO and TTE was modest when all intensities were included (R2 = 0.32) but strengthened when 25% was excluded (R2 = 0.72), indicating possible distinct tolerance behaviour at the lowest relative intensity. In resistance exercise, TTE also decreased with increasing %1RM (25%: 11:43 ± 4:39 min; 35%: 9:34 ± 5:39 min; 50%: 3:25 ± 1:04 min; 75%: 1:41 ± 0:34 min), with a significant modality × intensity interaction (F = 4.083, p = 0.041). Cycling trials at ≥35% PPO reached high physiological strain (RPE ≥18; lactate >8 mmol·L⁻¹; minimal SmO2 ~10–12%).
CONCLUSION:
Tolerance behaviour in cycling scaled to %PPO appeared comparable, yet distinct, from that observed in resistance exercise prescribed as %1RM, with reduced dispersion at higher relative intensities. This pattern suggests that PPO-based scaling may align with severe and extreme intensity tolerance. Accordingly, %PPO could represent a practical reference for characterising high intensity efforts, pending further definition of the PPO–duration relationship and accompanying physiological responses.